function showLayer(LayerName)
{
  setVisibility(LayerName,'visible');
}

function hideLayer(LayerName)
{
  setVisibility(LayerName,'hidden');
}
function setVisibility(LayerName,Wert) {
  if(document.all || document.layers || document.getElementById) {
    var obj=document.all ? document.all[LayerName].style : document.layers ? document[LayerName] : document.getElementById(LayerName).style;
    obj.visibility = Wert;
  }
}
function preload() {
  if (!document.images) return;
  var ar = new Array();
  var arguments = preload.arguments;
  for (var i = 0; i < arguments.length; i++) {
    ar[i] = new Image();
    ar[i].src = arguments[i];
  }
}